如何验证dd / mm / yyyy，数字贷款金额，字母首字母，姓氏。我在使用这个论坛时遇到了麻烦。感谢您的回复如此之快！
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<script type="text/javascript">
<!--//
function validate(form){
var message = 'Please fill in the following fields:\n\n\t';
for(var i=0; i<form.elements.length; i++){
if(form.elements[i].value.length == 0){
message+= form.elements[i].name.toUpperCase()+'\n\t';
}
}
message+= '\nOK submit incomplete form';
message+= '\nCANCEL return to the form';
message = confirm(message);
if(!message){ return false };
else{ return true };
}
//-->
</script>
</head>
<body>
<form name="loanform" action="processform.htm" method="get" onsubmit="return validate(this)">
First Name: <input type="text" name="firstname" maxlength="15"><br>
Last Name: <input type="text" name="lastname" maxlength="15"><br>
Birth Date: <input type="text" name="birthdate" maxlength="8"><br>
Loan Amount: <input type="text" name="loanamount" maxlength="6" ><br>
Years: <input type="text" name="years" maxlength="2"><br>
<br>
<input type="reset" value="clear">
<input type="submit" value="submit">
</form>
</body>
</html>
答案 0 :(得分：0)
您可以使用这样的功能。它为每种类型的字段设置一个正则表达式，然后创建一个表，说明哪个正则表达式用于哪个表单元素。它使用命名的表单元素来访问各个值。
function validate(form) {
var nameRE = /^[A-Za-z \.]+$/;
var dateRE = /^(\d{1,2})\/(\d{1,2})\/(\d{4})$/;
var amountRE = /^\$?[\d\.,]+$/;
var yearsRE = /^\d+$/;
var formItems = [
{name: "firstname", re: nameRE, tag: "First Name"},
{name: "lastname", re: nameRE, tag: "Last Name"},
{name: "birthdate", re: dateRE, tag: "Birth Date", isDate: true},
{name: "loanamount", re: amountRE, tag: "Loan Amount", min: 50000, max: 750000},
{name: "years", re: yearsRE, tag: "Years", min: 5, max: 30}
];
var item, val, num, month, day, year, valid, matches, incomplete = false;
var msg = 'Please fill in the following fields:\n\n\t';
for (var i = 0; i < formItems.length; i++) {
item = formItems[i];
// strip leading or trailing whitespace
var val = form[item.name].value.replace(/^\s+|\s+$/g, "");
form[item.name].value = val;
// see if it matches the regex
valid = item.re.test(val);
if (valid && item.isDate) {
matches = val.match(item.re);
month = parseInt(matches[1], 10);
day = parseInt(matches[2], 10);
year = parseInt(matches[3], 10);
if (month <= 0 || month > 12 ||
day <= 0 || day >= 31 ||
year < 1900 || year > 2020) {
valid = false;
}
}
if (!valid) {
incomplete = true;
msg += item.tag + '\n\t';
} else {
if (item.min && item.max) {
// clear out non-numeric chars
val = val.replace(/[,\$\s]/g, "");
// convert to a number
num = parseInt(val, 10);
// compare to min and max
if (num < item.min || num > item.max) {
incomplete = true;
msg += item.tag + " (must be between " + item.min + " and " + item.max + ")\n\t";
}
}
}
}
if (incomplete) {
msg += '\nOK submit incomplete form';
msg += '\nCANCEL return to the form';
return(confirm(msg));
}
return(true);
}
答案 1 :(得分：0)
要做的一种方法是使用类来了解给定input所需的验证类型。此外，您可以使用title属性对input进行更人性化的表示。
您的HTML将如下所示：
<form name="loanform" action="processform.htm" method="get" onsubmit="return validate(this)">
First Name (text only): <input class="validate-text" title="First Name" type="text" name="firstname" maxlength="15"><br>
Last Name (text only): <input class="validate-text" title="Last Name" type="text" name="lastname" maxlength="15"><br>
Birth Date (format dd/mm/yyyy): <input class="validate-date" title="Birth Date" type="text" name="birthdate" maxlength="8"><br>
Loan Amount (US dollars, numeric only): <input class="validate-number" title="Loan Amount" type="text" name="loanamount" maxlength="6" ><br>
Years (numeric only): <input class="validate-number" title="Years" type="text" name="years" maxlength="2"><br>
<br>
<input type="reset" value="clear">
<input type="submit" value="submit">
</form>
你的JavaScript函数（正则表达式似乎是最好的方法）：
function validate(f) {
var message=new Array(); //will contain the fields that are misfilled
var reText=new RegExp("^[a-z \-'\.]+$", "i"); //a RegExp to match names: only letters, "-", "'" and "." allowed
var reDate=new RegExp("^[0-9]{2}/[0-9]{2}/[0-9]{4}$"); //a RegExp to match a date in the format dd/mm/yyyy
var reNumber=new RegExp("^[0-9]+$"); //a RegExp to match a number
for(var e in f.elements) { //loop on every input of the form
var test=null; //set or reset the RegExp to use for the current input
var input=f.elements[e]; //assign the input to a var (easier to type, not needed)
if(!input.className) //if this input doesn't have any class declared
continue; //then we skip the rest of the loop to keep going with the next input
var classes=input.className.split(" "); //maybe the input has several classes, so we split them in a "classes" array
for(var c in classes) { //we loop on every class of the current input
switch(classes[c]) { //and we test if the current class of the current input is one of the classes we're interested in
case "validate-text": //if it is a text
test=reText; //the variable "test" will contain the RegExp we want to use
break;
case "validate-date": //same for a date
test=reDate;
break;
case "validate-number": //and same for a number
test=reNumber;
break;
default: //if the class is not something we want, nothing to do
break;
} //end switch
} //end classes loop
//here test is either null (no "validate-something" class found for the current input), or it contains the RegExp telling us the kind of input we must validate.
if(test!=null && !input.value.match(test)) { //if it is not null and if the input's value does not match the RegExp
message.push(input.title); //we add the field to the "message" array
}
} //end input loop
if(message.length>0) { //if the arary is not empty, we display a confirm box
return confirm("Please correctly fill the following field(s), or click OK to send an incomplete form:\n"+message.join("\n"));
}
//otherwise, the form is correctly filled, we return true to submit the form
return true;
}